As reported to the FAA. Reports are unverified, and codes are left as the FAA publishes them.
What was found
PILOT REPORTED IN CLIMB POWER, AIRCRAFT YAWED AND SEVERE ENGINE VIBRATION ENSUED. UPON INSPECTION MAINTENANCE FOUND THE CYLINDER TO HAVE ZERO COMPRESSION AND THE EXHAUST VALVE BROKEN AT THE STEM. THE CYLINDER WAS REPLACED WITH NO FURTHER DEFECTS NOTED.